Process of bending laminated sheets



1932- J. MESSING PROCESS OF BENDING LAMINATED SHEETS Filed April 17,1930 3 Sheets-Sheet l IN VEN TOR.

A TTORNE Y.

Aug. 1932- J. MESSING PROCESS OF BENDING LAMINATED SHEETS Filed April17, 1950 3 Sheets-Sheet 2 INVENTOR. BY 2 ATTORNEY.

Aug. 16, 1932. 55 1,872,482

PROCESS OF BENDING LAMINATED SHEETS Filed April 1'7, 1930 5 Sheets-Sheet'3 Q r I? /01 ff fi i A TT ORNE Y.

for bending such materials, including bending Patented Aug. 16, 1932tosEPH vrnss'me} or nn'rrtor'r, MICHIGAN, nssIGnoR 'ro jaunt;Doe};nnnozrmolrrtoiiuod:s oomrniw, or nnrnommronrenn, 'A conronerron orwnsr'vmerivra' rnocnss or nnnnnjve A nc tibn med" April 17,

This invention relatest-o improvements in the art of bendingcertain'non-metallic brit- --'tle materials. I

die stamped or cast by the manufacturer of the material, at greatexpense and inconvenience to the electrical manufacturer.

It is an object of this invention, therefore,

to provide'a method or process by which certain electrically insulatingparts could be made from a sheet of the insulating material, the processincluding the steps ofcutting the part from the material and bending itto shape.

In the bending of such materials, however, it has been foundthatportions on the remote side of the line of bend are subjected toten- 1 sile stresses and that these portions were ruptured or weakened,since the material is of a class which can stand no tensile stresses.

It is also an object, therefore, of this invention to provide a processfor bending such ma- 5 p for the apparatus of 'Figs..1-3. and 14. v

Fig.1? shows a cup formed by the improved 7 terials in which pressure isapplied to the material during the bending to eliminate the possibilityof tensile stresses arising therein.

It is a further object to provide apparatus or forming dies andportions'other than the forming portions for imparting compressionstresses to the material thru the plane thereof, the application ofcompression being continuous and being of such a character that tensilestresses therein are eliminated.

A further object is to' providea process for bending materials whichcannot be heated beyond acertain point because of their tendency to run,these materials, however, being capable of being heated up to a certainpoint to render them substantially flexible.

A further object is to provide a process proved process of thisinvention.

Fig. 4 1s 'a'view of a machine forbending LAMINATE SHEETS 1930. "Serialno.144'5,'1 o6.

such materials, as contrasted with bends of a large radius which presentno difliculty.

.Still other objects willireadily occur to those skilled in the artuponreference to the following description: and the accon'r panyingdrawings in which i l Fig. l shows,.to greatly enlarged scale, a crosssection of a bent. n

Fig. 2- shows the same material bent by old and wellknown processes. i iFig; 3 shows the material'bent by the n imsheetsof the material.

Fig; 5 is another view ofthe'sam'e'. Fig. 6 is a sectional view' ofFig.4 on the line 66, parts being removed for clarity.

carrying out the process of this invention. 1" Figs, Sand 9"show;bendingtrolls. 1 Fig. 10 is a view ofatube'fwith'aflexible mandrel therein i If f Fig.11' is a view of thesame injit's bent position. H Fig. 12 is aview ofan apparatus-forclosing the ends'of-tubest I v Figs. 13 and 14show apparatus f f ming cups by vention.

the process of the present in- Figs. 15 and 16 show compression shoesprocess. p Referring to the draw1ngs, a-port1on of The layers 20and 21are saturated'both in their fibers and in their intersticeswith the'productof layer 22. The width of the portion is indicated by thedimension'linelX.

Whenit is desired to'bend the material,

three-ply material to be i and apparatus forming sharpbends- Fig. 7 is aview ofanother machine for Q heat is applied thereto, renderingthesame.

' more or less flexible, the temperature being maintained below therunning point of the phenol condensation product, and the material isthen bent. It bent by' certain old and well known. processes the innerside of the bend retains the dimension X and the outer side of the bendbecomes considerably larger than the dimension X due to tensioning ofthe material at the portion B and perhaps due to a rupture therein. Ifbent by the improved process of thepresentinvention,

the material will attain the shape of Fig. 3, the outer side of the bendretaining the dimension X and the inner side being comressed-toadimension considerably less than l, as will be observed;

It will be noted that the fibers of the outer side of the bend remainintheir normal states while the fibers on the inner side are compressed,becoming considerably stronger than they were originally.

Apparatus The process of the present invention can be carried out byapparatus disclosed in Figs. 4 to 16 inclusive, which apparatus forms apart of the invention.

7 Sheet bending A stationary table 30 (Fig. 4) having pivotally attachedthereto at the axis 31 a movable table 32 forms a bed upon which thematerial 33 is disposed. A die member 34 is held in a slot 35 in theextension 37 on the table 30 by means of aknurled set screw machine ofFig. 4 to warm the material along the line of bending. However, anyother .means may be provided, if desired, to heat the material at .thispoint. 7

In carrying out the process, first the material is heated slightly torender it flexible, then it is placed on the tables, which are in theposition of Fig. 4; then it is clamped between the fixed stop 4O and themovablestop 42. Then, by means of suitable mechanism (not shown) thetable 32 is swung to the position shown in Fig. 5, the movable stop 42causing the material 33 to be compressed between it and the stop40 whilebending, as

indicated in Fig. 5. It will be noted that the axis. of bendingindicated by the abutment 38 is at-some distance from the axis of swingof the stop 42 and that, therefore, the stop 42 will cause theapplication of compression to the materialin the plane thereof, afterthe material has been partially bent without compress on.

. Continuous bending -The. process of the present invention can posedteeth 58a on the pusher 53.

roll 54 from the be utilized for the continuous bending of sheets, rods,etc., by means of the apparatus disclosed best in Figs. 7 to 9.Stationary guides and 51 between which is disposed a sheet 52 of thematerial form a guide for the pusher plate 53 which is caused toconstantly apply a compression vforce to the rear end of the material52. The forward end of the latter is projected between the forming rolls54 and 55 one-of which, namely, roll 55, is driven by means of thedriving wheel 56 which in turn drives the counterwheel 57 having teeth58 engaging with similarly dis- Since the roll portion of the wheel 55is slightly smaller in diameter than the pitch line of the gear teeth,it will benoted'that the pusher travels at a slightly greater speed thanthe circumference of the roll 55 and accordingly constantly applies acompression force to the material 52.-

If desired, roll 54 is made adjustable on the machine by means of thehandle 59 attached to the roll 54 atGO and to the machine at 61, thehandle being provided with a nut and bolt device 62 riding in the slot63. Movement of the handle 59 about the point 61 and in the slot 63causes movement of the position it is now shown as R06 2 bending I Ifdesired, the rolls'disclosed in Figs. 8 and occupying.

9 1nay be substituted for the rolls 54 and 55 to bend rods insteadv offloat sheets, the rolls 70, a, 71 and 71a being substituted for therolls 54 and 55, the material being fed into a space 72, 72a toassuniethe shape of the latter.

Tube bending When it is desired to bend tubing by the improved process,the apparatus of Figs. 10 and 11 is used in connection with theapparatus of Figs. 7 and 9 inclusive. The tubing indicated at isprovided with a mandrel including a back or abutment portion 81 rivetedto a flexible member 82 upon which is disposed an abu'tment83, flexibleelements 84, and a nut 85, the tube 80 being clamped between abutments81 and 83 by drawing up the nut 85. The members 84, as disclosed inFigs. 10 and 11, are expansible and contractible, laterally andlongitudinally, to take up the distance between the side walls of thetube and also between 81 and 83, that is to say, the distance Y and soas to form in effect, av solid rod which can be fed thru the rolls 70and 71 in the manner described above. After the tube is bent the nut 85is loosened which allows members 84 to contract to make it easy towithdraw the mandrel from the bent tube which carries out the process ofthe present invention.

I Tube closing When it is desired to close the ends of tubing by theprocess of the present invention, a tube 90 is inserted in the die 91and plungers 92 and 93 are projected inwardly to abut the material. Theplunger 93 first advances into die 91 to the position shown, thenplunger 92 applies compression by means of extension 94 through theplane of the material against the cup bottom While the inner walls areforced around spherical shape end of 93 thus carrying out the process ofthe present invention. The usual knock out or ejector may be provided,if desired.

Gap forming The process of the present invention can be utilized informing cups of the form disclosed in Fig. 17, by means of the apparatusof Figs. 13 to 16 inclusive. A disc 100 of the material is secured tothe shoes 101 and under the dies 102 and 103. A compound plunger elementhaving a shell 104 in which is a central plunger 105 and a shoesupporting means 106 forces the material against movable dies 102 and103 in a manner which Will be readily observed, the shoes 101 movinginwardly from the position shown in Figs. 13 to 15 to the positiondisclosedin Figs. 14 and 16, continuously applying compression at 108,movement of the shoes 101 being caused by the beveled portion 109 of theshell 104. Continued movement of the plunger 105 in the taper 110 of thedie 102 causes the cup to change from the shape disclosed in Fig. 1 1 tothe shape disclosed in Fig. 17, and in this further step it is notnecessary to apply compression to the material since the latter is nolonger being sharply bent on its curved portion 112, the side walls 113of the latter being merely swung upon the line 112 as a pivotal line.How ever, if it is desired compression can be applied tothe material byapparatus whose construction can be designed by the application of meremechanical skill.

It will thus be observed-that a process has been provided for formingelectrically insulating members or parts from sheets, rods, tubes, etc.,of the insulating material, and that apparatus has been provided forcarrying out such process.

It will also be noted that a process for bending materials of the classabove described, to very small radii, has been provided, a process whichin no way injures the fibers of the material, and which does not weakenthe material at the bending line.

If found necessary, a lubricant of suitable nature may be provided toprevent adhesion of the warmed material to the bending, rolling orforming dies.

Now having described the invention, and the preferred embodimentthereof, it is to be understood that the said invention is to belimited, not to the specific details herein set sure producing stressesacting in the plane of the sheet from opposite edges thereo 2. In theprocess of bending a sheet-like mass of a material which becomesflexible upon the application of heat, and which cannot resist tension,the steps of heating said material to a point to render it flexible,bending said material by stresses acting transverse to the plane of thesheet, and applying thereto, while it is beingbent, pressure pro- Jducing stresses acting in the plane of the sheet from opposite edgesthereof.

3. The process of bending material which becomes flexible at hightemperatures and which cannot resist tensile stresses, Which includesthe steps of rendering said material flexible, applying forces to thematerial to bend it and simultaneously applying pressure thereto whileit is being bent, in directions transverse to those of the forces usedfor bending, to prevent the arising of tensile stresses in the material.

4. For bending a non-metallic material of a type which becomes flexibleat high temperatures and which cannot resist tensile stresses and whichis brittle at ordinary temperatures, apparatus including means to renderthe material flexible, means to bend the material, and means to applycompression stresses to the material to prevent the arising of tensilestresses therewithin, said compression means being operable upon thematerial from opposed points and thru the plane of the latter andtowards the bending points thereof. b

5. For bending a non-metallic material of a type which becomes flexibleat high temperatures and which cannot resist tensile stresses and whichis brittle at ordinary temperatures, apparatus including means to renderthe material flexible, means to bend the material, and means to applycompression stresses tothe material to prevent the arising of tensilestresses therewithin, said compression means being operable upon thematerial from opposed points thru the plane of the latter and towardsthe bending point thereof, resistance to said compression means beingoffered by the material being bent.

J OSEPH' MESSING.

